1. Field of the Invention
This invention relates to an antimicrobial composition comprising indole and selected naturally occurring substances whose combination shows greater antimicrobial activity, particularly against P. aeruginosa and/or against P. acnes than does each component alone.
2. Description of the Prior Art
Microorganisms contaminate foodstuffs, cosmetics, and pharmaceutical products. Currently available disinfectants to control such harmful microorganisms are hinokitiol, benzoic acid (or its sodium salt), salicylic acid, p-hydroxybenzoic acid, etc.
Despite the wide use of these disinfectants, they do not appear to be effective against certain bacteria, particularly Pseudomonas aeruginosa (P. aeruginosa). P. aeruginosa is noted as a pathogen which causes serious infections in hospitals, clinics and at home. Although such disinfectants as o-phenylphenol and tert-alkyl ammonium salts are especially being used to control P. aeruginosa, they do not effectively inhibit the microorganism.
Accordingly, there is a definite need for antimicrobial compositions that are effective against P. aeruginosa and are safe for continuous and repetitive use.
Acne vulgaris is a common skin disorder. The typical skin lesions include blackheads (open comedones), whiteheads (closed comedones), and localized areas of inflammation (papules and pustules). The areas of skin commonly affected by acne are face, chest and upper back, where pilosebaceous units are concentrated. It is believed that Propionibacterium aches (P. acnes) plays a key role in the pathogenesis of acne. This bacterium resides in the pilosebaceous canal and produces a lipase that hydrolyzes triglycerides to free fatty acids in sebum. The free fatty acids thus generated are believed to cause both inflammation and comedones.
Currently, several medicaments are available to treat acne. These medicaments include benzoyl peroxide; retinoic acid; antibiotics such as tetracycline and erythromycin; and estrogens such as ethinyl estradiol. None of these drugs is completely free from side effects. For example, upon application of retinoic acid, erythema and exfoliation are commonly observed. Retinoic acid is also known to cause increased incidence of cutaneous tumors in experimental animals which receive the topical application of retinoic acid followed by UV light exposure.
Accordingly, a search continues for more improved antimicrobial compositions that are effective against P. acnes and are safe for continuous and repetitive use as an anti-acne agent.
The present combination of indole with one or more naturally occurring substances provides desirable enhancement in the antimicrobial activity of the naturally occurring substances.